Adjustable Hydraulic Coupling For Drilling Tools And Related Methods

ABSTRACT

An adjustable hydraulic coupling device allows simultaneously mounting of different parts of a downhole drilling tool to the drill string near its upper and lower extremities. This top- and bottom-mounting is made to points on the drill string separated by an indeterminate length. The coupling device allows a mechanical and sealed fluid connection between two portions of the tool, and allows assembling of both portions of the drilling tool into one functional unit, and allows both axial translation and rotational motion therebetween. A cylindrical protruding tube is attached to the portion of the drilling tool mounted at its upper extremity while a mating cylindrical tube is attached to the part of the drilling tool mounted near the bottom. During assembly, the smaller tube enters the larger tube and provides a sealed fluid path and also allows for the engagement length of the assembly to vary as required.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication Ser. No. 62/451,538, filed Jan. 27, 2017, and thatapplication is incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

In general, the present invention relates to a device or system capableof allowing a downhole drilling tool to be simultaneously mounted at twodifferent axial locations to a drill string while allowing the length ofthe tool to vary as required to accommodate such mounting locations.Specifically, the present invention discloses a hydraulic couplingdevice that allows the top portion of the tool and the bottom portion ofthe tool to be mounted to the drill string at points on the drill stringthat are separated by an indeterminate length and still allow amechanical and sealed fluid connection between the two portions. Thus,this invention allows a drilling tool to potentially use both a topmounted telemetry or sensor system and a bottom mounted mud pulsetelemetry system simultaneously.

In the drilling of deep bore holes, the rotary drilling technique hasbecome a commonly accepted practice. This technique involves using adrill string which consists of numerous sections of hollow pipeconnected together and to the bottom end of which a drill bit isattached. By imparting axial forces onto the drilling bit and byrotating the drill string either from the surface or using a hydraulicmotor attached to the drill string, a reasonably smooth and circularbore hole is created. The rotation and compression of the drilling bitcauses the formation being drilled to be crushed and pulverized.Drilling fluid is pumped down the hollow center of the drill stringthrough nozzles on the drilling bit and then back to the surface aroundthe annulus of the drill string. This fluid circulation is used totransport the cuttings from the bottom of the bore hole to the surfacewhere they are filtered out and the drilling fluid is re circulated asdesired. The flow of the drilling fluid also provides other secondaryfunctions such as cooling and lubricating the drilling bit cuttingsurfaces and exerts a hydrostatic pressure against the borehole walls tohelp contain any entrapped gases that are encountered during thedrilling process. To enable the drilling fluid to travel through thehollow center of the drill string, the restrictive nozzles in thedrilling bit and to have sufficient momentum to carry cutting and debrisback to the surface, the fluid circulation system at the surfaceincludes a pump or multiple pumps capable of sustaining sufficientlyhigh pressures and flow rates, piping, valves and swivel joints toconnect the piping to the rotating drill string.

The need to measure certain parameters at the bottom of a bore hole andprovide this information to the driller has long been recognized. Theseparameters include, but are not limited to the temperature, pressure,inclination and direction of the bore hole, vibration levels,inclination, azimuth, toolface (rotational orientation of the drillstring), but also include various geophysical and lithologicalmeasurements and formation geophysical properties such as resistivity,porosity, permeability, and density as well as insitu formation analysisfor hydrocarbon content. The challenge of measuring these parameters inthe hostile environment at the bottom of a borehole during the drillingprocess and conveying this information to the surface in a timelyfashion has led to the development of many devices and practices.

It is an advantage to be able send data from the bottom of a bore wellto the surface, while drilling, and without the use of wires or cables,and without the continuous and/or frequent interruption of drillingactivity. Thus, tools commonly referred to as “measurement whiledrilling” or “MWD” tools have been developed. Several types of MWD toolshave been contemplated in the prior art and are discussed in briefbelow.

MWD tools may transmit data in several ways, including: creating EM (lowfrequency radio waves or signals, currents in the earth or magneticfields) waves to propagate signals through the earth; imparting highfrequency vibrations to the drill string which can be used to encode andtransmit data to the surface; and creating pressure pulses to encode andtransmit data to the surface of the earth from the bottom of a borehole.

MWD tools using pressure pulses can operate in a number of ways, suchas: closing or opening a valve in the drill string so as to create asubstantial pressure pulse that is detectable at the surface when aparticular parameter reaches a pre-selected or particular value orthreshold, or creating a series or group of pulses depending upon theparameter's value, or by using the time between the pressure pulsesignals in addition to the total number of pressure pulse signals toencode information. Opening and closing and sensing may be accomplishedmechanically or electronically or electromechanically, or by acombination thereof.

MWD tools of the types described are limited in that they arenon-reciprocating in nature. The measurements in such devices are madewhen the fluid flow is stopped for a short period of time and the datais transmitted only once when the fluid flow resumed. Acquiring downholemeasurements while drilling with a device that can measure parameterswhenever desired (not just when the fluid flow is interrupted) and cantransmit these parameters to the surface continuously or when desiredwould be an advantage.

Such an MWD drilling tool may include a pulsing mechanism (pulser)coupled to a power source (e.g, a turbine generator capable ofextracting energy from the fluid flow), a sensor package capable ofmeasuring information at the bottom of a well bore, and a controlmechanism that encodes the data and activates the pulser to transmitthis data to the surface as pressure pulses in the drilling fluid. Thepressure pulses may be recorded at the surface by means of a pressuresensitive transducer and the data decoded for display and use to thedriller.

A pulser may create pressure pulses in a number of fashions. In oneembodiment, a servo mechanism opens and closes the main pulsingmechanism indirectly. Here, the fluid flow does most of the work ofopening and closing the main valve to generate pulses to transmit data.Other representative examples of servo driven pulser mechanisms havebeen proposed in U.S. Pat. Nos. 3,958,217, 5,333,686 and 6,016,288. Inanother embodiment, the pulse is created not by creating a restrictionto the flow of drilling fluid in the hollow center of the drill string,but by opening a closing a port on the side of the drill string. Thismethodology, often referred to as “a negative pulser”, creates pressuredecreases (as opposed to pressure increases) as venting fluid through aport in the drill string allows for some portion of the fluid to bypassthe nozzles in the drilling bit. In another, hybrid, embodiment, apositive pulser (one capable of creating positive pressure pulses) iscoupled with a negative pulser (one capable of creating negative pulses)to provide the ability to create pressure pulses of various shapes andsizes by combining the action of both types of pulsers. And yet anotherembodiment is the “siren” type pulsing mechanism, which creates positivepulses of reasonable magnitude in rapid succession and in a continuousfashion (as opposed to creating single pulses on demand). This generatesa hydraulic carrier wave, over which data may be transmitted to thesurface by varying the frequency of the pulses being generated or bycreating phase shifts in the carrier wave. Other examples of siren typepulsers are proposed in U.S. Pat. Nos. 3,309,656 and 3,792,429.

Such data delivery systems, whether EM, Acoustic or Mud Pulse, haveparticular inherent limitations which make use in all applicationschallenging. For example, EM systems are often limited by the depth theycan be used to due to the inherent attenuation of the earth's rockformations. Acoustic telemetry systems are also limited by depth due tothe length of the drill string and by the attenuating effects of thefriction of the drill string against the borehole, which tend to retardthe transmission of the acoustic sound pulses to the surface. Mud pulsetelemetry tools are generally more robust and can be used in mostapplications; however, these tools are bandwidth limited and aregenerally not able to provide data at a high rate.

Using multiple telemetry methods may allow data to be delivered fromdeeper wells using one transmission device while using the secondtransmission device to provide faster data at shallower depths. Or incertain situations, using multiple devices may allow data to betransmitted effectively faster by utilizing both data channels tosimultaneously transmit different data. It may also be desirable to havemultiple transmission devices and allow one to be used in certainportions of the well while the other is used in a different portion tooptimize the frequency and density of the data being sent to thesurface.

Thus, a primary goal in the design of such multiple telemetry MWD toolsis to provide technologies and methods that can be designed,manufactured and installed is such a way as to allow multiple telemetrymethods to be used simultaneously.

Using multiple telemetry methods simultaneously can be challenging dueto the nature of the drilling process & how the telemetry methods work.Mud pulse telemetry tools are generally mounted to one extremity or theother of the downhole drilling tool because they require the porting orobstruction of the drilling fluid to create pressure pulses in the fluidflow. In such cases, a different or secondary telemetry device mustnecessarily be mounted at a different location on the drilling tool.This combined drilling tool is usually many feet in length and needs tobe attached to portions of the drill string where the distance betweenthose portions may vary (even between nominally identical equipment.Moreover, such a drilling tool may need to straddle or fully passthrough a single piece of non-magnetic drill string, itself of variablelength, to enable proper sensor measurements. Thus, in such a case, anMWD tool is mounted on one end of a single non-magnetic drill collar(with, e.g., a mud pulse telemetry device at that end) and also at theopposite end (with, e.g., a second telemetry device, such as EM, at thatend). In these case, the length of that non-magnetic drill collar maynot be known in advance and/or may vary from the nominal length.

An extensible or variable-length member or module in the drilling toolmay allow for easy installation and usage of such multiple telemetrydevices.

SUMMARY OF THE INVENTION

A new and improved apparatus, system, and method of use are presentedthat allow for the assembly of a tool incorporating multiple telemetrydevices onto a drill string with the capability to adapt to varyinglength of the drill string components such as a non-magnetic drillcollar.

A method and apparatus are provided to adjust the length of a multipletelemetry-method capable drilling tool and allow a sealed fluid paththrough the adjustable apparatus for using in actuating a mud pulser ortransmitting a signal in the fluid column. A novel hydraulic couplingmechanism of adjustable length is assembled inline to a drilling tool,typically including a mud pulser telemetry device and one or more othertelemetry devices. The assembled apparatus or “MWD Tool” can be attachedabove and below a non-magnetic drill collar (NMDC) in respectivehang-off or landing collars, and can span the length of the NMDC whileallowing portions of the tool to be mounted and fixed in space to boththe top, hang off, collar and the bottom, landing, collar.

A system and method are provided to allow a mud pulse telemetry systemto be installed at the bottom part of the MWD Tool and have a secondarytelemetry system, either EM, Acoustic or a second mud pulse telemetrysystem, to be installed at the top portion of the MWD tool. The systemand method also provide a hydraulic coupling between components of a mudpulse telemetry system. The bottom portion of the MWD tool is bothmounted near the bottom of the NMDC to a landing collar andsimultaneously the top portion of the MWD Tool is mounted to a hang-offcollar above the NMDC. In addition, the hang-off collar may be used tolocate and mount a device other than a secondary telemetry system, andcould be used instead to mount any number of sensors or devices thatrequire a fixed mounting location above the NMDC.

In this respect, before explaining at least one embodiment of theinvention in detail, it is to be understood that the invention is notlimited in this application to the details of construction and to thearrangements of the components set forth in the following description orillustrated in the drawings. The invention is capable of otherembodiments and of being practiced and carried out in various ways.Also, it is to be understood that the phraseology and terminologyemployed herein are for the purpose of description and should not beregarded as limiting. As such, those skilled in the art will appreciatethat the conception upon which this disclosure is based may readily beutilized as a basis for the designing of other structures, methods, andsystems for carrying out the several purposes of the present invention.It is important, therefore, that the claims be regarded as includingsuch equivalent constructions insofar as they do not depart from thespirit and scope of the present invention.

Therefore, it is an object of the present invention to provide anextensible hydraulic coupling and mounting mechanism or apparatus andmethod of using the same, and a MWD tool system and method of using thesame, that are robust and durable and of reliable construction, may beeasily and efficiently manufactured and marketed, and at low cost, thatare simple to assemble and require minimal training and time to assembleand operate, reduce or eliminate the susceptibility of being obstructedby contaminants and additives in the drilling fluid, are capable ofdownhole operations off-shore and under water, are usableinterchangeably in all types of wells, and with various types oftelemetry devices.

Further objects of the present invention are to provide a new hydrauliccoupling apparatus and method of using the same with a reasonably smallcross section that minimizes the pressure drop associated with usethereof with a servo-assisted main pulser, and that does notsignificantly impede the flow of drilling fluid on its way to the bitduring normal drilling operations and thus will significantly reduceerosion and wear that is caused due to the high flow velocities of thedrilling mud.

A further object of the present invention is to provide a new hydrauliccoupling apparatus and method of using the same that is short in length.This short length may allow the MWD tool, and specifically the hydrauliccoupling apparatus to be built to be stiffer and without the need forspecial flexible members to allow for the curvature of the bore hole.This added stiffness also permits the MWD tool to have greaterresilience in the presence of high vibration and shock levels that arefound in the bottom of a bore hole while drilling.

A further object of the present invention is to provide a new hydrauliccoupling apparatus and method of using the same which provides amechanism to adequately shock isolate the internal components of the MWDTool from the damaging effects of axial vibration imparted through thebottom landing sub, and reduce the occurrence and severity of damagecaused by excessively high vibrations in the drilling environment.

A further object of the present invention is to provide an extensiblehydraulic coupling and mounting mechanism or apparatus and method ofusing the same, and a MWD tool system and method of using the same, thatprovide a mechanism to allow for variations in the length of the drillstring components between mounting points for the MWD Tool, such as thelength of an NMDC and allow for such variations to be accommodatedrapidly, easily and effectively during the assembly of the MWD Tool intothe NMDC, the hang-off collar and the landing collar.

A further object of the present invention to provide a hydrauliccoupling apparatus and method of using the same that is able to berapidly installed or uninstalled from the MWD Tool to minimize andeliminate valuable time and cost at the drilling rig.

A further object of the present invention is to provide a hydrauliccoupling apparatus and method of using the same that can be manufacturedin multiple different lengths to tailor effective to different ranges oflengths of the drill string components between mounting points for theMWD Tools, while still allowing a sufficient and reasonable amount oflength adjustment to easily and effectively install the MWD Tool intothe drill string.

A further object of the present invention is to provide a new hydrauliccoupling apparatus and method of using the same that providesdiametrically stabilizing bearings and multiple insertion and extractionfeatures to allow the coupling apparatus to be installed and uninstalledeasily and effectively in instances where the upper portion of the MWDTool and the lower portion of the MWD Tool are not reasonablyconcentric.

A further object of the present invention is to provide a new hydrauliccoupling apparatus and method of using the same that provides a robustsliding seal system that is able to accommodate the translation of thehydraulic apparatus during installation without sacrificing the qualityor effectiveness of the pressure sealing between the inner and outerportion of the apparatus.

These, together with other objects of the invention, along with thevarious features of novelty which characterize the invention, arepointed out with particularity in the claims annexed to and forming apart of this disclosure. For a better understanding of the invention,its operating advantages, and the specific objects attained by its uses,reference should be had to the accompanying drawings and descriptivematter in which there are illustrated preferred embodiments of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a representative sketch of parts of the surface and downholeportions of a drilling rig.

FIG. 2 is a representative sketch of various components that togethermay comprise the downhole portion of an MWD Tool resident inside thetubular components of the drill string.

FIG. 3 is a three dimensional view of the tubular components of thedrill string inside which the MWD Tool may reside.

FIG. 4 is a three dimensional view of the various components thattogether may comprise part of the MWD Tool.

FIG. 5 is a partial cutaway of the lower portion of the MWD Toolresident inside the tubular components of the drill string.

FIG. 6 is a three dimensional view of the adjustable hydraulic couplingshown in an unassembled state.

FIG. 7 is a three dimensional view of the adjustable hydraulic couplingshown in its maximally extended and engaged state.

FIG. 8 is a three dimensional view of the adjustable hydraulic couplingshown in its minimally extended and engaged state.

FIG. 9 is a partial cutaway of the adjustable hydraulic couplingresident inside the non-magnetic drill collar.

FIGS. 10A & 10B are three dimensional views of the upper portion of theMWD Tool mounted into a hang-off sub.

FIG. 10C is a partial cutaway three dimensional view of the upperportion of the MWD Tool mounted into a hang-off sub and inside the NMDC.

FIGS. 10D & 10E are three dimensional views of the lower portion of theMWD Tool mounted into a landing sub.

FIGS. 10F & 10G are partial cutaway three dimensional views of the upperportion of the MWD Tool mounted into a hang-off sub and inside the NMDCand the lower portion of the MWD Tools mounted into a landing sub.

DETAILED DESCRIPTION

In an embodiment of the invention, information of use to the driller ismeasured at the bottom of a bore hole relatively close to the drillingbit and this information is transmitted to the surface using pressurepulses in the fluid circulation loop. This information, or otherinformation, may also be transmitted using a secondary telemetry devicewhich could be a second mud pulser transmitter, an EM telemetry deviceor an acoustic telemetry device. Some of the data thus gathered totransmit may be acquired from sensors or systems that are mounted to thedrill string near the top or bottom of the MWD Tool.

The command to initiate the transmission of data is sent by stoppingfluid circulation and allowing the drill string to remain still for aminimum period of time. Upon detection of this command, the downholetool measures at least one downhole condition, which is usually ananalog signal. The signal is processed by the downhole tool and readiedfor transmission to the surface. When the fluid circulation isrestarted, the downhole tool waits a predetermined amount of time toallow the fluid flow to stabilize and then begins transmission of theinformation by repeatedly closing and then opening the pulser valve togenerate pressure pulses in the fluid circulation loop. The sequence ofpulses sent is encoded into a format that allows the information to bedecoded at the surface and the embedded information extracted anddisplayed.

It is also possible that a command to initiate transmission is sent bydifferent means, including by transmitting EM signals down to the MWDTool which may have a receiver to accept such command, or throughvibrations in the drill string sent to a vibration sensitive detectorincluded as part of the MWD Tool. Such additional command methods, incombination or independent of the first method, may initiate datatransmission using one or both transmission methods, or may initiate anynumber of other functions that the downhole MWD Tool can perform.

Referring now to the drawings and specifically to FIG. 1, there isgenerally shown therein a simplified sketch of the apparatus used in therotary drilling of bore holes. Bore hole 10 is drilled into the earthusing rotary drilling rig 11 which consists of derrick 12, drill floor14, draw works 16, traveling block 18, hook 20, swivel joint 22, kellyjoint 24 and rotary table 26. Drill string 30 used to drill bore hole 10is made up of multiple sections of drill pipe that are secured to thebottom of kelly joint 24 at the surface. Rotary table 26 is used torotate the entire drill string 30 assembly while draw works 16 is usedto lower drill string 30 into bore hole 10 and apply controlled axialcompressive loads. The bottom of drill string 30 is attached to multipledrilling collars 32, which are used to stiffen the bottom of drillstring 30 and add localized weight to aid in the drilling process. Ashort piece of drill collar called a hang-off sub 32 (or hang-offcollar) is positioned below multiple drilling collars 32. A length ofnon-magnetic drill collar (NMDC) 36 is position below hang-off sub 34.Below NMDC 36, a second short piece of drill collar called a landing sub38 is attached.

In some drilling operations, a hydraulic turbine of a positivedisplacement type (not shown) may be inserted below landing sub 38 toenhance the rotation of the drill string desired. In addition, variousother drilling tools such as stabilizers, one-way valves and mechanicalshock devices (commonly referred to as jars or agitators) may also beinserted in the bottom section of drill string 30 either below or aboveNMDC 36. Some of these components could be used in the process ofdirectionally drilling the well. As a representation of a hydraulicturbine or any such optional device, tubular component 40 is shownattached below landing collar 38. At the bottom of drill string 30, andbelow optional tubular component 40, drilling bit 42 is attached.

The drilling fluid or “mud” is usually stored in mud pits or mud tanks50, and is sucked up by mud pump 52, which then forces the drillingfluid to flow through surge suppressor 54, then through kelly hose 56,and through swivel joint 22 and into the top of drill string 30. Thefluid flows through drill string 30, through drill collars 32, throughhang-off sub 34, through NMDC 36, through landing collar 38, throughtubular component 40 and through drilling bit 42 and its drillingnozzles (not shown). The drilling fluid then returns to the surface bytraveling through annular space 60 between outer diameter of drillstring 30 and well bore 10. When the drilling fluid reaches the surface,it is diverted through mud return line 62 back to mud tanks 50.

The pressure required to keep the drilling fluid in circulation ismeasured by pressure sensitive transducer 70 on kelly hose 56. Themeasured pressure is transmitted as electrical signals throughtransducer cable 72 to surface computer 74 which decodes and displaysthe transmitted information to the driller.

In situations where multiple telemetry devices are used downhole as partof an MWD Tool, additional sensors may be placed at or near drilling rig11 to measure any pertinent information required to receive and decodethe data being sent from the downhole tool which resides inside and issubstantially part of the drill string. Such sensors may be electricalin nature, as shown by ground current sensing electrode 76 which isattached to the earth some distance from drilling rig 11, and whose datais sent to surface computer 74 through cable 78. Other sensors may alsobe attached to the drilling rig itself, preferably at a location closeto the center of well bore 10 and in good electrical contact withdrilling rig 11. Such a sensor 90 is shown attached to surface casingpipe 82 of drilling rig 11 and whose signals are transmitted to surfacecomputer 74 through cable 80. It will be clear to those familiar withthe art that multiple other such sensors could be attached at, on ornear the drilling rig to measure magnetic fields, electrical currents,vibrations or any number of other parameters which may aid in thedetection and decoding of the data being sent from a downhole tool.

FIG. 2 generally shows a schematic representation of the variouscomponents that together make up the downhole portion of an MWD Tool.Downhole MWD Tool 100 is generally installed inside and along centerlineA-A of the tubular components that form part of drill string 30,specifically hang-off sub 34, NMDC 36 and landing collar 38, and isgenerally disposed in the presence of the fluid flow from surface pumps52 to drill bit 42.

The MWD Tool may include a top mounted device 102. Top mounted device102 could be a secondary telemetry device such as an EM transmitter, anacoustic transmitter or a sensing device. A common feature of topmounted device 102 is that it needs to be mounted to hang-off sub 34.Top mounted device 102 might need to make good electrical contact withhang-off sub 34 to enable the transmission of electrical signals by anEM telemetry device, or need to make good mechanical contact with thehang-off sub 34 to enable transmission of acoustic signals by anacoustic telemetry device, or need to be connected to the hang-off sub34 to enable taking of measurements, such examples as measuring thepressure of the annular fluid 60. Top mounted device 102 may be mountedto hang-off sub 34 in such ways as bolts, or other fasteners that willwithstand the forces imposed by a downhole tool.

MWD Tool 100 also may include one or more tubular modules. FIG. 2depicts multiple tubular modules 104 and 106 which are connected to thebottom of top mounted device 102. Historically, MWD Tools have beenbuilt in such tubular and modular fashion to allow for easy transport,testing and assembly and for this reason, two different such tubularmodules 104 and 106 are shown. Tubular modules 104 & 106 may providenecessary functions such as storing and providing power to MWD Tool 100using batteries, contain other sensors or systems necessary for themeasurement and transmission of data, house control electronics, powergeneration systems or any contain equipment for other functions requiredby MWD Tool 100.

MWD Tool 100 also includes mud pulse telemetry device 108 which isattached to the bottom of tubular modules 104 and 106. The purpose ofthis mud pulse telemetry device is actuate a valve to impede the flow ofthe drilling fluid and generate pressure pulses. This mud pulsetelemetry device may be a servo pulser, such as one described in U.S.Pat. No. 9,133,950 (issued Sep. 15, 2015) or a direct mud pulser, suchas one described as part of a measurement while drilling apparatus inU.S. Pat. No. 7,735,579, or a negative pulser. (Both preceding U.S.Patents are incorporated by reference in their entirety.) Mud pulsetelemetry device 108 may contain one or a plurality of fluid inlets 110through which the part of the drilling fluid pumped by mud pump 52 thatis present in annular space 92 may flow into mud pulse telemetry device108. Ultimately, pressure pulses can be transmitted through the fluidcolumn existing in annular space 60 to the surface, and used to encodeand transmit data from the subterranean environment to the surface.

Female hydraulic coupler 112 is attached to the bottom of mud pulsetelemetry device 108, and the fluid entering fluid inlet(s) 110 may flowthrough female hydraulic coupler 112. This fluid flow through mud pulsetelemetry device 108 may be intermittent as may be required for theproper operation of the system and this intermittent flow may beachieved by mud pulse telemetry device 108 opening and closing a valve(not shown) that may reside internal to the mud pulse telemetry device.A representative valve of this type is described in detail in U.S. Pat.No. 9,133,950.

FIG. 2 also shows male hydraulic coupler 114 partially inserted intofemale hydraulic coupler 112 to form hydraulic coupling system 111. Thedepth of this insertion may vary as required and such a variation isachieved by allowing male hydraulic coupler 114 to slide in or out offemale hydraulic coupler 112 to achieve the proper spacing required.

Main pulser valve 116 is attached to the bottom of male hydrauliccoupler 114. Main valve 116 is used to generate pressure pulses used toencode and transmit data from the bottom of the well bore to thesurface, and this generation may be activated by the intermittent flowof fluid from annular cavity 92 going through fluid inlet(s) 110,entering mud pulse telemetry device 108 and then flowing through a valve(not shown) inside said mud pulse telemetry device 108, and then furtheron through female hydraulic coupler 112, and then through male hydrauliccoupler 114 to activate main pulser valve 116.

Placement of male hydraulic coupler 114 and female hydraulic coupler 112could be reversed (not shown), to have male hydraulic coupler 114attached to mud pulse telemetry device 108 and inserted into femalehydraulic coupler 112 from above.

The bottom of the main pulser valve 116 is attached to main pulser mount118, which in turn is mechanically connected to landing sub 38. Mainpulser valve 116 may be hydraulically coupled to main pulser mount 118,and main pulser mount 118 to landing sub 38. Landing sub 38 may providea port (not shown) therein to annular space 60 to permit movement ofdrilling fluid and transmission of pulses thereinto.

Mechanically attaching top mounted device 102 to hang-off sub 34 andsimultaneously mechanically attaching main pulser mount 118 to thelanding sub 38 without the presence of the hydraulic coupling system 111consisting of the female hydraulic coupler 112 and the male hydrauliccoupler 114 would be extremely challenging. This challenge arises fromthe fact that the lengths of hang-off sub 34, NMDC 36 and landing sub 38may vary significantly. Variations may arise from several sources,including different nominal lengths, manufactured variances from nominallengths, and variances from nominal lengths arising from sources such asrecutting threads (which can shorten the drill string components). Inaddition, the act of attaching hang-off sub 34, NMDC 36 and landing sub38 together as part of drill string 30 requires that they be rotatedrelative to each other to tighten threads joints (not shown), and suchrotation cannot be accomplished if both ends of MWD Tool 100 areattached to their respective mounting locations. Sliding engagement ofmale hydraulic coupler 114 with female hydraulic coupler 112 is free,subject to friction between the two, and does not transmit axial loadsbetween the connected devices (e.g. top mounted device 102 and mainpulser valve 116).

In other embodiments (not shown), mud pulse telemetry device 108 doesnot use a second telemetry device to create mud pulses in annular space60. In such embodiments, mud pulse telemetry device 108 comprises adirect mud pulser or a negative pulser. In either case, mud pulsetelemetry device 108 may generate pulses by the intermittent flow offluid from annular cavity 92 going through fluid inlet(s) 110, enteringmud pulse telemetry device 108 and then flowing through a valve (notshown) inside said mud pulse telemetry device 108, and then further onthrough hydraulic coupling system 111. In the case of a negative pulser,the fluid may flow from the hydraulic coupling to outside the system,without a valve. Hydraulic coupling system 111 is, however, mechanicallyconnected and hydraulically coupled to landing sub 38 via mount 118.Landing sub 38 may provide a port (not shown) therein to annular space60 to permit movement of drilling fluid and transmission of pulsesthereinto.

FIG. 3 generally shows a three dimensional view of the tubularcomponents inside whom MWD Tool 100 in generally disposed. Hang-off sub34 is attached to NMDC 36 to which in turn landing sub 38 is attached.

FIG. 4 generally shows a three dimensional view of MWD Tool 100. Topmounted device 102 is shown attached to tubular module 104, which inturn is connected to tubular module 106, and further on to mud pulsetelemetry device 108. Mud pulse telemetry device is shown with fluidinlet ports 110, and mud pulse telemetry device is in turn attached tohydraulic coupling system 111 at female hydraulic coupler 112.

FIG. 4 also shows male hydraulic coupler 114 partially engaged andinserted into female hydraulic coupler 112. Male hydraulic coupler isalso attached to main pulser valve 116, which in turn is attached tomain pulser mount 118.

FIG. 4 also shows location 122 on top mount device 102, which is onepossible location where top mount device 102 could be attached tohang-off sub 34. In addition, location 124 is also shown on main pulsermount 118, which is one possible location where main pulser mount 118could be attached to landing sub 38.

FIG. 4 also shows a plurality of centralizers 120, which are arepresentation of devices that may be used to hold MWD Tool 100concentric to the inner diameter of NMDC 36. These centralizers 120could be made in many shapes and sizes, and may utilize elastomers,springs or other members to provide adequate support for MWD Tool 100inside NMDC 36.

FIG. 5 shows a cross-section of a portion of MWD Tool 100 residentinside the tubular collars attached to drill string 30. Specifically, itshows a portion of the bottom section of MWD Tool 100 inside the lowerend of NMDC 36 and the upper end of landing sub 38. In the interest ofclarity, the bottom end of a representative mud pulse telemetry device108 similar to one described in U.S. Pat. No. 9,133,950 is shownattached to the upper end of female hydraulic coupler 112, and in thefurther interest of clarity, a representative main pulser valve 116 andmount 118 are shown without any salient details.

FIG. 6 shows a three dimension view of hydraulic coupling system 111 inone of its embodiments, where the male hydraulic coupler 112 and thefemale hydraulic couple 114 are shown in an unengaged state, anddisplays the two portions of hydraulic coupling system 111 prior toassembly. FIG. 6 also shows the plurality of radial seals 140 and radialbearing 142, and end fittings 113 and 115.

FIG. 7 shows a three dimension view of hydraulic coupling system 111 inone of its embodiments, where male hydraulic coupler 112 and femalehydraulic couple 114 are shown in the maximally extended and engagedstate.

FIG. 8 shows a three dimension view of hydraulic coupling system 111 inone of its embodiments, where the male hydraulic coupler 112 and thefemale hydraulic couple 114 are shown in their minimally extended andengaged state.

FIG. 9 shows a cross-section of a portion of the MWD Tool residentinside the tubular collars attached to the drill string 30.Specifically, it shows the engagement of male hydraulic coupler 112 andfemale hydraulic coupler 114 inside NMDC 36. Female hydraulic coupler114 includes sealing surface 141 on which plurality of radial seals 140and radial bearing 142 act. The seal created between sealing surface 141and radial seals 140 seals hydraulic flow path 91 from annular space 92.Hydraulic flow path 91 permits hydraulic coupling system 111 tohydraulically couple devices attached at its respective end fittings 113and 115.

To further explain the components and for purposes of convenience andclarity, the following will describe individual sections of theadjustable hydraulic coupling device as shown in FIGS. 4, 5 and 9 whilereferring to FIGS. 6, 7 and 8 which show portions of the MWD Tool 100and details of the adjustable hydraulic coupling in a three dimensionalview.

Top mounted device 102 can be attached to hang-off sub 34 in differentways, but generally, MWD Tool 100 must be mounted inside hang-off sub 34so as to prevent rotation between MWD Tool 100 and hang-off sub 34. Thisneed for rotational alignment is due to the need to measure and transmitthe rotation position of the downhole components as measured by anyinertial sensing system to enable the drilling of directional wellbores.In addition, any such mounting may also need to be thus rotationallyaligned to enable access to fluid ports, sensor ports or other devicesor means to enable the proper measurement or transmission of data. Inaddition, such rotational alignment may also be a consequence of theneed to axially align top mounted device 102 inside hang-off sub 34 forsubstantially the same reasons.

A downhole tool also needs to be mechanically coupled to a drill stringto reduce the damaging effects of the shock and vibrations that areroutinely encountered during the drilling of wellbores. Thus, it is anecessary result that any top mounted device 102 will need to be mountedso as to prevent both axial and radial movement between it and hang-offsub 34.

Main pulser mount 118 will also need to be mounted inside landing sub 38to prevent rotation between main pulser mount 118 and landing sub 38.This need for rotational alignment shares substantially the same reasonsas those described above for top mounted device 102. However, inaddition to the foregoing, bottom mounted main pulser valve 116 may alsoneed said mounting to allow for proper operation of the pulser valvesystem to generate pressure pulses.

Thus a multiple telemetry MWD Tool 100 may require that both its top andbottom extremities be mounted to components of drill string 30,specifically and respectively hang-off sub 34 and landing sub 38, insuch a way as to prevent both extremities from translating axially orrotating relative thereto.

However, due to the nature of the components generally used in therotary drilling of wellbores, such multiple locations of mounting arechallenging to accomplish. It is well known by those familiar with thedrilling of wellbores that the lengths of hang-off sub 34, NMDC 36 andlanding sub 38 vary substantially. These variations are usually causedby the routine inspection and rethreading of the helical threadedconnections (not shown) on these tubular components, which necessarilyreduces their length. Such length changes result in the need for MWDTool 100 to be able to vary the length as required between the points atwhich it mounts to allow for the mounting it to both the upper extremityand the lower extremity.

In addition, the act of mechanically engaging the tubular components andtightening their threaded connections cannot be accomplished withoutallowing some part of MWD Tool 100 to spin or rotate relative to therest of MWD Tool 100. A lack of such a rotational capability will resultin the twisting of MWD Tool 100 to the point of destruction.

To enable this need to both change the length of MWD Tool 100 and toallow said MWD Tool 100 to have part of it rotate relative to anotherpart of itself, a hydraulic coupling device such as is described belowmay be used.

As mentioned previously, hydraulic coupling system 111 is placed betweenthe bottom of mud pulse telemetry device 108 and main pulser valve 116.This is to enable the drilling fluid present in annular space 92 in theinner volume of NMDC 36 to enter inlet port(s) 110 of mud pulsetelemetry device 108 and to be intermittently allowed to flow throughthe bottom of mud pulse telemetry device 108 due to the action of servovalve 130. When servo valve 130 is opened, fluid from annular space 92is allowed to flow through inlet port(s) 110, through servo valve 130,and then further along cavity 134 and then into inner cavity 136 offemale hydraulic coupler 112. The drilling fluid then flows throughinner cavity 138 of male hydraulic coupler 114 and on to main pulservalve 116, where this fluid flow is used to activate main pulser valve116 to generate pressure pulses in the drilling fluid in annular space92.

It will be understood by those familiar with the art that inner cavities136 and 138, forming part of hydraulic flow path 91, need to besubstantially sealed from the fluid column in annular space 92 allowproper activation of main pulser valve 116. In addition, male hydrauliccoupler 112 and female hydraulic coupler 114 need to be relativelyconcentric to allow for easy assembly of MWD Tool 100 when its two subsections are brought together during assembly of NMDC 36 to landing sub38. In addition, male hydraulic coupler 112 and female hydraulic coupler114 being concentric facilitates free rotational motion between the two,such that they are not rotationally coupled. Thus, end fittings 113 and115 are likewise able to freely rotate relative to one another.

The sealing of inner cavities 136 and 138 is accomplished by a pluralityof radial seals 140 that are mounted onto male hydraulic coupler 114. AsNMDC 36 is axially aligned to landing sub 38 during the assemblyprocess, male upper end 146 of male hydraulic coupler 114 enters femalelower end 144 of female hydraulic coupler 112, and is guided so as toallow both male hydraulic coupler 114 and female hydraulic coupler 112to be positioned concentrically to each other before male upper end 146fully engages into cylindrical bore 137 of female hydraulic coupler 112.That engagement causes radial seals 140 to also enter cylindrical bore137 of female hydraulic coupler 112, to seal with sealing surface 141and thus create a tight seal impeding the connection of fluid betweeninner cavities 136 and 138, hydraulic flow path 91, and fluid column 92.

To further enable said engagement, female lower end 144 is proved with alarge smooth conical chamfered surface 145, and the male upper end isprovided with a large smooth filleted surface 147 to ensure that theengagement is not impeded by the presence of mechanical discontinuitiesthat would retard said engagement or damage radial seals 140.

In addition, the outer diameter of male hydraulic coupler 114 isprovided with radial bearing 142 to allow male hydraulic coupler 114 tobe held relatively concentric to female hydraulic coupler 112. Radialbearing 142 is preferably made in the plain bearing style and preferablyuses a material with a low coefficient of friction which can sustain thechemically abrasive nature of the drilling fluids found in the wellbore.A material such a ToughMet® or PEEK may be used. Radial seals 140 andradial bearing 142 also facilitate male hydraulic coupler 114 and femalehydraulic coupler 112 being rotationally decoupled, and that endfittings 113 and 115 are likewise rotationally decoupled.

During assembly of NMDC 36 to landing sub 38, the engagement length ofmale hydraulic coupler 114 inside female hydraulic coupler 112 may varyas required to allow for the proper shouldering of NMDC 36 to landingsub 38, and to further thread NMDC 36 and landing sub 38 to be threadedtogether.

To further enable the ability of male hydraulic coupler 114 to engageeffectively into cylindrical bore 137 of female hydraulic coupler 112,the upper end of female hydraulic coupler 112 is provided withcentralizing fins 120 mounted onto MWD Tool 100 at said location.Centralizing fins 120 may be formed or rubber or other materials, andmay be retained using bolts 132. Centralizing fins 120 may be providedat other locations along MWD tool 100. Other types of centralizingdevices may also be used, such as bow springs or integrated fins as theapplication demands.

The foregoing thus describes an adjustable hydraulic coupling that maybe used in downhole tools to enable easy assembly of said tools into thedrill string components while simultaneously allowing for adjustment ofthe length of the downhole tools to be mounted on both extremities ofthe tool, and allow said drilling tool to be assembled inside the drillstring components by the act of rotationally threading the drill stringcomponents together without damage to the drilling tool.

Another embodiment may be the inversion of the foregoing describedinvention (not depicted) in which the mud pulse telemetry device and themain valve are mounted to a hang off sub mounted to the upper portion ofthe non-magnetic drill collar, and a bottom mounted device to be mountedto the landing sub, in which case, the final assembly step would be thethreading of the hang-off sub onto the top of the non-magnetic drillcollar.

Another possible embodiment may be one in which the fluid beingconnected between the mud pulse transmitter and the main valve is ahydraulic fluid instead of drilling fluid.

Yet another possible embodiment is one in which such an adjustablecoupling is made between sealed compartments between modules of the MWDtool. In this instance, the interval cavity of the adjustable couplingis used to connect wires or radio signals in lieu of connecting a fluid.

In the embodiment of the invention as described above, MWD Tool 100 isdescribed that is capable of measuring desired parameters at the bottomof a bore hole during the process of drilling, at when desired, is ableto telemeter this information to the surface from such a subsurfacelocation using a series of pressure pulses in the drilling fluid wherethe pressure pulses thus telemetered encode data about these desiredparameters which are then subsequently measure at the surface location,detected, decoded and the telemetered information is retrieved, stored,displayed or transmitted further as required. MWD Tool 100 is mountednear its bottom extremity to landing sub 38, which resides below NMDC36.

In addition, MWD Tool 100 also consists of a secondary telemetry deviceor sensor device, where said telemetry device or sensor device is a topmounted device 102 that is mounted near its top extremity insidehang-off sub 34.

MWD Tool 100 has disposed between its top extremity and bottom extremityhydraulic coupling system 111, which includes male hydraulic coupler 114mounted to the bottom part of MWD Tool 100 and female hydraulic coupler112 mounted to the top part of MWD Tool 100. Hydraulic coupling system111 has an internal cavity of variable and adjustable length and volumeto allow for easy assembly and functionality of MWD Tool 100.

In order to further explain the method of using the invention, and forpurposes of convenience and clarity, the following will describe theadjustable hydraulic coupling device as shown in FIGS. 4, 5 and 9 whilereferring to FIGS. 6, 7 and 8, which show portions of the MWD Tool 100and details of the adjustable hydraulic coupling in a three dimensionalview, and FIGS. 10A through 10G which show the assembly process by whichthe invention can be used in one embodiment of the invention.

FIG. 10A generally depicts a three dimensional view of the upper portionof the MWD Tool 100 which is shown mounted into hang-off sub 34. Theupper portion of MWD Tool 100 as shown in FIG. 10A consist of a topmounted device 102, tubular modules 104 and 106 attached to top mounteddevice 102, and mud pulse telemetry device 108. These components thatmake up the upper portion may contain a plurality of centralizationdevices 120, which preferably are built into each individual module andserve to provide radial stabilization of the upper portion of the MWDTool 100 when it is inserted into further components described below. Itshould be noted that top mounted device 102 is axially and rotationallylocated to hang-off sub 34 using any number of possible mounting devices(not shown).

FIG. 10B generally depicts a three dimensional view of the upper portionof the MWD Tool 100 substantially described in FIG. 10A, having femalehydraulic coupler 112 attached to the lower end thereof. Femalehydraulic coupler 112 is designed to allow fluid entering inlet port(s)110 of mud pulse telemetry device 108 to be intermittently allowed toflow through the inner diameter of female hydraulic coupler 112 asrequired to allow the activation of devices described below.

FIG. 10C generally depicts a three dimensional view of the upper portionof MWD Tool 100 substantially as described in FIGS. 10A and 10B, asinserted into NMDC 36, and with NMDC 36 threaded onto hang-off sub 34.For purposes of clarity, NMDC 36 is shown partially cut away to show thedetails of MWD Tool 100 resident substantially inside NMDC 36. Theprocess of inserting MWD Tool 100 into NMDC 36 and threading NMDC 36 tohang-off sub 34 positions MWD Tool 100 generally concentric to the innerdiameter of NMDC 36. Such concentricity is facilitated by the pluralityof centralization devices 120. The lower extremity of the upper portion148 of MWD Tool 100 (female lower end 144 of female hydraulic coupler112 at this point in the process) is thus located some distance abovethe lower end of NMDC 36, and substantially inside the inner diameterthereof.

FIG. 10D generally depicts a three dimensional view of lower portion 148of MWD Tool 100, including main pulser valve 116. Main pulser valve 116is mounted to landing sub 38. It should be noted that main pulser valve116 is axially and rotationally located to landing sub 38 using anynumber of possible mounting devices (not shown).

FIG. 10E generally depicts a three dimensional view of lower portion 150of MWD Tool 100 mounted inside landing sub 38 as substantially depictedin FIG. 10D, to which male hydraulic coupler 114 is attached. Aplurality of radial seals 140 and a radial bearing 142 are mounted tomale hydraulic coupler 114. Male hydraulic coupler 114 is designed witha cavity through its entire length, including inner cavity 138 so as toallow fluid entering male upper end 146 to travel through said malehydraulic coupler 114 and enter main pulser valve 116 to activate saidmain pulser valve 116 which in turn creates pressure pulses which may beused to encode data for transmission to the surface.

FIG. 10F generally depicts a three dimensional view of upper portion 148and lower portion 150 of MWD Tool 100, in which upper portion 150 ismounted to hang-off sub 34, and a substantial portion of MWD Tool 100 isresident inside NMDC 36, and lower portion 150 is mounted to a landingsub 38. Both those portions of MWD Tool 100 are shown concentric to eachother as a depiction of their relative positions before assembly of thetwo parts of MWD tool 100.

In an embodiment, lower portion 150 is aligned relatively concentric toupper portion 148 and lower portion 150 is inserted gently into upperportion 148, thereby inserting male hydraulic coupler 114 into therelatively circular hole that makes up the inner diameter of NMDC 36.This act of insertion eventually causes the upper extremity of lowerportion 150, male upper end 146 of male hydraulic coupler 114, to enterthe lower extremity of upper portion 148, female lower end 144 of femalehydraulic coupler 112. Then it causes radial seals 140 and radialbearing 142 to engage in cylindrical bore 137 of female hydrauliccoupler 112. This causes female hydraulic coupler 112 to be movedconcentric with male hydraulic coupler 114 and creates a sealed cavityinside male hydraulic coupler 114 and female hydraulic coupler 112.

Additional movement of landing sub 38 towards NMDC 36 causes malehydraulic coupler 114 to engage further into female hydraulic coupler112. The sealed internal cavity will be reduced in length and volume asrequired until such a point that the landing sub 38 may be threaded toNMDC 36 and then torqued as required to tighten said landing sub 38 toNMDC 36. This act of threading will cause male hydraulic coupler 114 torotate relative to female hydraulic coupler 112 (and end fittings 113and 115 likewise to rotate relative to one another), but such rotationwill not cause any damage to either component or MWD Tool 100 ingeneral, and will continue to retain the sealing integrity of theinternal cavity.

Referring to FIGS. 10C and 10E, the lengths of male hydraulic coupler114 and female hydraulic coupler 114 and of cylindrical bore 137 may bevaried during manufacturing to achieve the required lengths to allow forproper engagement of the female hydraulic coupler 114 into the malehydraulic coupler 114 as appropriate.

As the length of hang-off sub 34, NMDC 36 and landing sub 38 may varydue to manufacturing and maintenance reasons, a hydraulic couplingsystem as described will allow these aforementioned three tubularcomponents to be attached and threaded to each other, whilesimultaneously allowing MWD Tool 100 substantially retained inside thesetubular components to be assembled, and further allow such MWD Tool tobe both top mounted at hang-off sub 34 and bottom mounted at landing sub38. In addition, the invention described in this document and the methodfor the utilization of said invention as described above, will allow MWDTool 100 with multiple mounting locations and potentially multipletelemetry devices to be assembled and utilized for intended purpose oftelemetering data from the bottom of a wellbore to the surface using mudpulses in the fluid flow and potentially utilizing other telemetrymethods in conjunction.

1. A variable length hydraulic coupling for creating a flowpath fordrilling fluid in a downhole tool, comprising: two hydraulic fittingends; a male coupling shaft; and a female receiving tube; said shaft andtube hydraulically coupling said ends creating a drilling fluid flowpaththerebetween; and said shaft and tube permitting rotation between saidfitting ends during assembly of said downhole tool.
 2. The hydrauliccoupling of claim 1, further comprising: said shaft and tube permittingaxial translation between said fitting ends.
 3. The hydraulic couplingof claim 1, further comprising: said coupling having a longitudinalaxis; said shaft extending along said axis from a first of saidhydraulic fitting ends; and said tube extending along said axis from asecond of said hydraulic fitting ends; and said tube defining a receivervoid aligned with said axis.
 4. The hydraulic coupling of claim 3,further comprising: said tube having a receiver end exposing saidreceiver void; said coupling shaft and receiver void hydraulicallycoupling said fitting ends.
 5. The hydraulic coupling of claim 3,further comprising: a first portion of said receiver void having asubstantially cylindrical shape in the longitudinal axis; a secondportion of said receiver void being chamfered to be larger away fromsaid second hydraulic fitting.
 6. The hydraulic coupling of claim 1,further comprising: said shaft comprising an exterior shaft coupler;said exterior shaft coupler comprising one or more hydraulic seals andone or more radial bearings; said shaft being slidably engageable withsaid tube along said exterior shaft coupler.
 7. A downhole tool,comprising: a variable length hydraulic coupling comprising twohydraulic fitting ends; a male coupling shaft; and a female receivingtube; said shaft and tube hydraulically coupling said ends creating adrilling fluid flowpath therebetween; and said shaft and tube permittingrotation between said fitting ends during assembly of said downholetool; and a first downhole telemetry device; said first telemetry devicemechanically coupled to a first of said fitting ends.
 8. The downholetool of claim 7, further comprising: said shaft and tube permittingaxial translation between said fitting ends.
 9. The downhole tool ofclaim 7, further comprising: a second downhole telemetry device; saidsecond downhole telemetry device mechanically coupled to a second ofsaid fitting ends.
 10. The downhole tool of claim 9, further comprising:said variable length hydraulic coupling hydraulically coupling saiddownhole telemetry devices.
 11. The downhole tool of claim 9, furthercomprising: said variable length hydraulic coupling permitting axialtranslation and rotation between said downhole telemetry devices duringassembly of said drilling tool.
 12. The downhole tool of claim 7,further comprising: said first downhole telemetry device mounted to afirst sub; a second downhole telemetry device; said second downholetelemetry device mounted to a second sub; and said variable lengthhydraulic coupling forming a hydraulic connection between said firstdownhole telemetry device and said second downhole telemetry device;wherein the length of said variable length hydraulic coupling adjustswhile said subs are translate axially relative to one another.
 13. Thedownhole tool of claim 12, further comprising: a non-magnetic drillcollar; wherein each of said subs is connected to an opposite end ofsaid drill collar; and said first downhole telemetry device comprises amain pulser valve.
 14. The downhole tool of claim 12, furthercomprising: a downhole tubular component connected at opposite endsthereof to said first and second subs.
 15. The downhole tool of claim 7,further comprising: a first hydraulic flowpath between a second of saidfitting ends and said first downhole telemetry device; and a downholecomponent containing said variable length hydraulic coupling; saiddownhole component and said variable length hydraulic coupling formingan annular space therebetween; and said annular space forming a secondhydraulic flowpath.
 16. The downhole tool of claim 15, furthercomprising: a second downhole telemetry device; said second hydraulicflowpath extending between said downhole telemetry devices.
 17. Thedownhole tool of claim 15, further comprising: said first hydraulicflowpath comprising said drilling fluid flowpath.
 18. A method ofassembling a downhole tool having a longitudinal axis, comprising:hydraulically coupling a variable length hydraulic coupling to a firsttelemetry device; said variable length hydraulic coupling comprising twohydraulic fitting ends; a male coupling shaft; and a female receivingtube; said shaft and tube hydraulically coupling said ends creating adrilling fluid flowpath therebetween; and said shaft and tube permittingrotation between said fitting ends during assembly of said downholetool; and said hydraulically coupling step comprising mechanicallycoupling said first telemetry device to a first of said fitting ends.19. The method of assembling of claim 18, further comprising: couplingsaid first telemetry device to a first sub in a position axially androtationally fixed thereto about said longitudinal axis.
 20. The methodof assembling of claim 18, further comprising: coupling a seconddownhole telemetry device to a second sub in a position axially androtationally fixed thereto about said longitudinal axis; said secondtelemetry device mechanically coupled to a second of said fitting ends.21. The method of assembling of claim 18: said hydraulically couplingstep further comprising engaging said shaft within said tube; creatingaxial translation between said fitting ends along said longitudinalaxis; and creating relative rotation between said fitting ends aboutsaid longitudinal axis.
 22. The method of assembling of claim 18,further comprising: said first telemetry device in a position axiallyand rotationally fixed to a first sub about said longitudinal axis; anda second of said fitting ends in a position axially and rotationallyfixed to a second sub about said longitudinal axis.
 24. The method ofassembling of claim 22: said hydraulically coupling step furthercomprising engaging said shaft within said tube; advancing said secondsub along said longitudinal axis toward said first sub; and rotatingsaid second sub about said longitudinal axis.
 25. The method ofassembling of claim 22, further comprising: connecting each of said substo an opposite end of a downhole tubular component.
 26. The method ofassembling of claim 25, further comprising: connecting each of said substo an opposite end of a non-magnetic drill collar.
 27. The method ofassembling of claim 25: said downhole tubular component comprising aplurality of downhole tubular elements.
 28. The method of assembling ofclaim 22, wherein: one of said first and second subs is a drill collar;and comprising connecting the other of said first and second subs to thedrill collar.
 29. The method of assembling of claim 22, furthercomprising: threadingly connecting the first and second subs to oneanother.
 30. The method of assembling of claim 18, further comprising:said hydraulically coupling step further comprising directlymechanically coupling said first telemetry device to a first of saidfitting ends.